Electric terminal



Oct. 25, 1960 A. J. HUMPHREY ELECTRIC TERMINAL 2 Sheets-Sheet 1 Filed Feb. 3, 1956 Fig.3

Oct. 25,1960 A. J. HUMPHREY ELECTRIC TERMINAL 2 Sheets-Sheet 2 Filed Feb. 3, 1956 Fig.9

INVEN TOR.

UM T/M MQ J m M 7 m F United ELECTRIC TERMINAL Andrew J. Humphrey, Cleveland, Ohio, assignor to The Reliance Electric & Engineering Company, a corporation of Ohio Filed Fell. 3, 1956, Ser. No. 563,358

10 Claims. (Cl. 339-50) tates Patent pins which slide into individual sockets making a slip-fit connection due to the resiliency of the metal forming each socket. It has been found that for heavy duty purposes, such as for power rectifier tubes of the gas filled or even vacuum type, the large current requirements of these tubes, for example, the filament terminals, have resulted in overheating at the tube socket due to poor electrical contact. This is especially aggravated on slipfit sockets which have been in use for some time because typically a person will wiggle a tube from side to side in order to loosen it to extract it from the socket.

The present invention is directed toward a socket for a tube or other electrical component which overcomes these difficulties of poor current carrying capacity.

An object of the invention is to provide a tube socket utilizing screw terminals which may be tightened onto spade lugs of .the electrical device to provide heavy duty current carrying capacity.

Another object of the invention is to provide a compact and easily manufactured tube socket.

Another object of the invention is to provide a tube socket made of a minimum of parts achieved primarily by duplication of identical parts to be fabricated into one socket.

Another object of the invention is to provide a tube socket wherein terminals for the filament leads of the tube may be closely spaced without hazard due to the low voltage on the filament.

Another object of the invention is to provide a screw terminal tube socket wherein terminals are presented at different angles so as to have easy access thereto by a screw driver.

Another object of the invention is to provide a screw terminal tube socket wherein the terminals are offset relative to a reference plane to provide spacing between the terminals for physical and electrical considerations.

Another object of the invention is to provide a screw terminal tube socket wherein the terminals are separated both by angular disposition and spacing relative to a reference plane to provide maximum screw driver accessibility to the terminals.

Another object of the invention is to provide a screw terminal tube socket wherein angular and level separation of the terminals is provided :on both ends of the socket, one end for the tube and the other end for conductor connection to the socket.

Another object of the invention is to provide a tube socket having conductor strips therein all of which are identical.

Other objects and a fuller understanding of this in- 2 vention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing, in which:

Figure l is a side view of the tube socket partially showing a tube connected thereto and with a cover broken away to show the socket construction;

Figure 2 is an end view of the terminals of the tube and socket but without the cover;

Figure 3 is an elevational view of one of the insulated body halves;

Figure 3A is a sectional view on line '3A-3A of Figure 1;

Figure 4 is an elevational view of the terminal cover;

Figure 5 is a sectional view on the line 55 of Figure 4;

Figure 6 is a bottom view of the insulator body half of a modification of the invention; 7

Figure 7 is a side view of a conductor strip used in the modification;

Figure 8 is a bottom view of the completed second embodiment; and

Figure 9 is a side view partially in section taken on the line 99 of Figure 8.

The Figures 1 and 2 show the preferred embodiment of the invention wherein the reference numeral 11 refers to the complete tube socket. This tube socket is made of first and second body halves 12 and 13 of insulating material. Each body half 12 and 13 may be identical which is a feature of the invention to provide ease and simplicity of manufacture and assembly. The two body halves 12 and 13 are also complementary and may be fastened together by bolts 14 extending through apertures 15 so that the two halves form a complete body 16. The body 16 has first and second longitudinal end portions 19 and 20 with a mounting flange 21 positioned between these two end portions. The mounting flange 20 is adapted to be mounted to a support or mounting panel 22 which may be conducting or non-conduting because the insulating of the body halves 12 and 13 insulate all live parts from the mounting panel 22. The mounting flange 21 may be mounted to the panel 22 by any suitable means such as mounting bolts 23.

The first end portion 19 has a longitudinally extending central finger 25 which extends along the length dimension of't-he socket 11. This central finger 25 has first and second flat faces 26 and 27 separated by a short insulated divider '28. First and second sloping shoulders 29 and 30 are also provided on the first end portion 19 separated by screw recesses 31 from the central finger 25. Apertures 32 may be provided in the end portion '19 to reduce the weight, and to provide better ventilation.

The second longitudinal end portion 20 is provided with first and second longitudinally extending spaced fingers 35 and 36 with a recess therebetween. This recess is defined by first and second diverging surfaces 37 and 38 which in turn are separated by .a dividing wall 39. Flat ends 40 are provided on the ends of the spaced fingers 35 and 36.

Each body half has first, second, third, and fourth longitudinal slots 41 through 44. The first and fourth slots 41 and 44 may be considered as a first pair of slots and are co-extensive .and are disposed in the first and second longitudinally extending spaced fingers 35 and 36. The second and third slots 4-2 and 43 may be considered as a second pair and are closely spaced and coextensive and are disposed in the longitudinally extending central finger 25. First through fourth conductor strips 45 through 48 are provided, each being identical and are disposed in the first through fourth slots 41 through 44. Each conductor strip has a right angled terminal foot and an obtuse angled terminal foot. Terminal feet 51 through- 54 are'disposed on the first end portion 19 of the body 16, and terminal feet 55 through 58 are disposed on the second longitudinal end portion 20. The Ohtuse angled terminal feet 51 and 54 lie adjacent to the sloping shoulders 29 and 30, and the right angled terminal feet 52 and 53 lie adjacent the flat faces 26 and 27. Similarly, the right angled terminal feet 55 and 58 lie adjacent the fiat ends 40, and the obtuse angled feet 56 and 57 lie adjacent the diverging surfaces 37 and 38. As shown in the assembled view of Figure 2, the second pair of conductor strips 46 and 47 are longitudinally displaced from the first pair of strips 45 and 46 approximately onefourth their length. Terminal screws 59 are provided in each of the eight feet, and the feet on the first end portion 19 are adapted to receive spade lugs 60 of the tube 61 or other electrical device. The terminal feet 55 through 58 on the second end portion 20 of the body are adapted to receive conductors for electrical connection to the socket 11.

The obtuse angled terminal feet may be at some angle such as one hundred degrees or one hundred twenty degrees from the main portion of the conductor strip, and approximately a one hundred eight degree angle has been shown so that the terminal feet 51 and 54 present the terminal screws therein at diverging angles relative to the angular disposition of the screws in the terminal feet 52 and 53. The terminal feet 52 and 53 may be considered to lie in a reference plane, and it will be noted that the terminal feet 51 and 54 are spaced from this reference plane to provide still greater physical spacing between all terminal feet on the first end portion 19. A screw driver has been shown by the dot-dash line 65 and represents a terminal tightening or loosening tool. It will be noted that such a screw driver 65 may have access to the four terminals on the first end portion 19 at four diiferent positions and at three different angular positions and two different levels or planar spacings. The two closely spaced terminal feet 52 and 53 may be for the filament if the electrical device 61 is an electronic tube; and because of the low voltage on such filament, such close spacing presents no hazard. The other terminal feet 51 and 54 may be for the grid and anode of such tube and thus the arrangement of terminals provides a maximum spacing for greatest tool accessibility and electrical insulation between the terminals.

The terminal feet on the second end portion 20 of the socket 11 also provide maximum tool accessibility. The terminal feet 55 and 58 are spaced differently from the reference plane than the terminal feet 56 and 57. Also, the obtuse angled terminal feet 56 and 57 present the terminal screws therein at converging angles so that a screw driver coacting with the screws in such feet will pass approximately equidistantly between the terminal feet 55 and 58. This provides screw driver access without danger of short circuiting any two of the terminal feet, and such screw driver access is provided by both different angular disposition as well as different levels or planes for both end portions of the tube socket. The conductor strips 45 through 48 are all identical with the middle pair inverted relative to the outer pair; and this, together with the body halves 12 and 13 being identical, provides a cheaply and simply manufactured tube socket as well as one which is easily assembled by unskilled personnel.

A cover 68 is made from insulating material and preferably one which can have some resiliency. The cover has a curved upper portion 69, legs 70 and 71, and a closed end 72. A peripheral stiffening rib 73 is formed on the inside; and in the assembled position, as shown in Figure 1, this rib 73 lies adjacent one face 74 of the end portion 19, and the closed end 72 lies adjacent the opposite face 75 of this end portion 19. Hooks 76 extend from the inner edge of the cut-out surface 77 on the closed end 72. This cut-out surface 77 provides some resiliency to spread the legs 70 and 71, and the hooks 76 drop in the apertures 32 to retain the cover 68 in place. This cover 68 physically covers the terminal feet 51 through 54 on the end portion 19 to prevent accidental contact by personnel with these terminal feet. With the tube 61 in place, only a small opening is permitted between the cover 68 and base of the tube 61.

The Figures 6 through 9 show a second embodiment of the invention illustrating your tube socket 80. This tube socket 80 is made of first and second insulated body halves 81 and 82 which are identical, and one of these has been shown in Figure 6. Each body half has a mounting flange 83 with holes 84 to receive hollow rivets 85 for fastening the two body halves 81 and 82 together in inverted and complementary relationship. Four conductor strips 88 are provided, each of which is identical. The strips have a notch 89 to receive a chock 90 disposed in a recess which is made of two depressions 91 in the inner face of the body halves. When the chock 98 is in place in the notch 89, the conductor strip 88 may not be pulled out from either end of the tube socket 80. The body halves 81 and 82 may be considered as first and second end portions of the tube socket with the mounting flange 83 therebetween. The conductor strips 88, when in place in the tube socket 80, have sections outboard of these end portions which are terminal feet 92 integral with and aligned with the respective conductor strips. Punched portions 93 may be provided on the terminal feet to pro vide a greater axial length of thread for terminal screws 94. Because of the punched portions 93, recesses 95 may be provided in the body halves 81 and 82 in order to assemble the tube socket.

As will be noted in the Figure 8, there may be provided a closely spaced pair of terminal feet which are aligned and disposed in a reference plane. Also, more widely spaced terminal feet may be provided spaced from this reference plane and disposed at an acute angle to this reference plane. The disposition of the terminal feet in the tube socket 80 may thus coincide with the disposition of the terminal feet 51 through 54 in the tube socket 11 of Figure 2 so that this tube socket 80 will receive the same tube 61. Also, it will be noted that the same relative positioning of terminals is provided on both sides of the tube socket 80 so that conductors may be connected to the terminal feet on the underside of the panel 96 with maximum screw driver accessibility to these terminals. Such screw driver accessibility to the terminals on both sides of the tube socket 80 will be provided because of the different angular spacing and level or planar spacing of the terminal feet.

It will be apparent that both tube sockets 11 or 80 might be made from a single insulated body member with the conductor strips in place such as by casting or molding rather than making such body from two separate pieces subsequently fastened together.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

l. A terminal comprising, first and second insulated body halves complementarily interfitting to form a body, said body having first and second longitudinal end portions with a mounting flange therebetween to mount to a mounting panel disposed generally perpendicular to the length dimension of said body, a longitudinally extending central finger on said first longitudinal end portion of said body, first and second sloping shoulders on said first longitudinal end portion lying on either side of said longitudinally extending central finger and longitudinally displaced from the end thereof, first and second longitudinally extending spaced fingers on said second longitudinal end portion of said body, a recess having diverging surfaces disposed between and longitudinally spaced from the ends of said first and second longitudinally extending spaced fingers, each body half having surfaces defining first, second, third, and fourth longitudinal slots disposed in that order, said first and fourth slots spaced apart and coextensive and lying in said first and second longitudinally extending spaced fingers, respectively, and said second and third slots being coextensive and together being longitudinally displaced from said first and fourth slots and lying in said longitudinally extending central finger, fastening bolts for fastening together said body halves in complementary relationship with the first through fourth slots of one body half being complementarily disposed adjacent the first through fourth slots, respectively, of the second body half, first, second, third, and fourth conductor strips each being substantially similar, a right angled terminal foot on one end of each conductor strip and an obtuse angled terminal foot on the other end of each conductor strip, said first through fourth conductor strips disposed in the eight slots in said body with said first through fourth conductor strips disposed in each adjacent pair of first through fourth slots, respectively, said first and fourth conductor strips having the obtuse angled feet thereof disposed adjacent said sloping shoulders in said first longitudinal end portion of said body and having the right angled feet thereof disposed adjacent the ends of said first and second longitudinally extending spaced fingers, said second and third conductor strips having the obtuse angled feet thereof adjacent said diverging surfaces in said second longitudinal end portion of said body and having the right angled feet thereof adjacent the end of said longitudinally extending central finger.

2. An electric terminal comprising, a body having two ends, mounting means on said body to mount same to a supporting panel, four conductor strips in said body each being identical, a terminal foot integral with each end of each of said strips, pairs of feet at the two ends of said body being disposed at different angles, a terminal screw threaded in each foot and adapted to secure a conductor thereto, means for mounting said four conductor strips in said body in substantially parallel directions and with two centrally disposed strips having one of said pairs of feet, apertures in one end of said body, and an insulated resilient cover having hooks engaging said apertures to retain said cover on said one body end, said body covering the four terminal feet on said one body end for electrical safety protection, and whereby the four terminal feet on each end of said body present the terminal screws therein at different angles at two different locations relative to a reference plane so that a tool may have access to said terminals with said cover removed.

3. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs in alignment, said screw terminal comprising, first and second insulated body halves complementarily engageable to form a body, said body having a first and .a second end portion with a mounting flange therebetween to mount to a mounting panel, means for fastening together said body halves in complementary relationship, said body having surfaces defining slots extending from said first to said second end portion, first, second, third, and fourth conductor strips disposed in said slots in said body with said first and fourth strips being a first pair and said second and third strips being a second pair, a terminal foot on one end of each strip at said first end portion, the terminal feet on said second pair of strips at said first end portion being disposed in a reference plane, the termintal feet on said first pair of strips at said first end portion being disposed at an acute angle to said feet on said second pair of strips and spaced from said reference plane, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said first end portion, and said conductor strips having terminal means whereby said pairs of terminal feet at said first end portion of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles to thus permit access to the terminal screws by a tool in different angular positions without short circuiting any two of the terminal screws.

4. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs in alignment, said screw terminal comprising, first and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, means for fasten-1 ing together said body halves in complementary relationship, said body having surfaces defining slots extending from said first to said second end portion, first, second, third, and fourth conductor strips disposed in said slots in said body with said first and fourth strips being a first pair and said second and third strips being a second pair, a terminal foot on each end of each strip, the terminal feet on said second pair of strips at said first end portion being disposed in a reference plane, the terminal feet on said first pair of strips at said first end portion being disposed at an acute angle to said feet on said second pair of strips and spaced from said reference plane, and at said second end portion the terminal feet on one pair of strips being at an acute angle to the terminal feet on the other pair of strips and with the two pairs of feet differently spaced relative to said reference plane, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said first end portion, whereby said pairs of terminal feet at said first and second end portions of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles to thus'permit access to the terminal screws by a tool in different angular positions without short circuiting any two of the terminal screws.

5. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs aligned, said screw terminal comprising, first, and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, means for fastening together said body halves in complementary relationship, said body having surfaces defining slots extending from said first to said second end portion, first, second, third, and fourth conductor strips all of substantially, equal length and disposed in said slots in said body with said first and fourth strips being a first pair and said second and third strips being a second, pair, a terminal foot on each end of each strip, the terminal feet on said second pair of strips at said first end portion being disposed in a reference plane, the terminal feet on said first pair of strips at said first end portion being disposed at an acute angle to said feet on said second pair of strips and spaced from said reference plane, and at said second end portion the terminal feet on one pair of strips disposed at an acute angle to the terminal feet on the other pair of strips and with the two pairs of feet differently spaced relative to said reference plane, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said first end portion, whereby said pairs of terminal feet at said first and second end portions of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles tothus permit access to the terminal screws by a tool in different angular positions without short circuiting any two of the terminal screws.

6. A screw'terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs aligned, said screw terminal comprising, first and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, means for fastening together said body halves in complementary relationship, said body having surfaces defining slots extending from said first to said second end portion, first, second, third, and fourth conductor strips all of substantially equal length and disposed in said slots in said body with said first and fourth strips being a first pair and said second and third strips being a second pair, each of said conductor strips being straight and having an exposed section outboard of each end of said body acting as a terminal foot each aligned with the respective conductor strip, the terminal feet on said second pair of strips at said first end portion being disposed in a reference plane generally perpendicular to said mounting flange, the terminal feet on said first pair of strips at said first end portion being disposed at an acute angle to said feet on said second pair of strips and spaced from said reference plane, and at said second end portion the terminal feet on one pair of strips disposed at an acute angle to the terminal feet on the other pair of strips and with the two pairs of feet differently spaced relative to said reference plane, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said first end portion, whereby said pairs of terminal feet at said first and second end portions of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles to thus permit access to the terminal screws by a tool in different angular positions without short circuiting any two of the terminal screws.

7. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs aligned and closely spaced, said screw terminal comprising, first and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, a central finger extending from said first end portion of said body, first and second sloping shoulders on said first end portion lying on either side of said central finger and longitudinally displaced from the end thereof, each body half having surfaces defining slots extending from said first to said second end portion, means for fastening together said body halves in complementary relationship, first, second, third, and fourth conductor strips disposed in said slots in said body halves with said first and fourth strips being a first pair and said second and third strips being a second pair and contained in said central finger, a right angled terminal foot on each of said second pair of strips disposed in a reference plane and adjacent the end of said central finger, an obtuse angled terminal foot on each of said first pair of strips adjacent said sloping shoulders, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs, whereby said pairs of right angled and obtuse angled terminal feet at said first end portion of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles to thus permit access to the terminal screws thereat by a tool in different angular positions without short circuiting any two of the terminal screws.

8. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs aligned and closely spaced, said screw terminal comprising, a first and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, a central finger extending from said first end portion of said body, first and second sloping shoulders on said first end portion lying on either side of said central finger and longitudinally displaced from the end thereof, each body half having surfaces defining slots extending from said first to said second end portion, means for fastening together said body halves in complementary relationship, first, second, third, and fourth conductor strips disposed in said slots in said body halves with said first and fourth strips being a first pair and said second and third strips being a second pair and contained in said central finger, a right angled terminal foot on each of said second pair of strips disposed in a reference plane and adjacent the end of said central finger, an obtuse angled terminal foot on each of said first pair of strips adjacent said sloping shoulders, said second end portion having a terminal foot on each strip with the terminal feet on one pair of strips at a different angle from the terminal feet on the other pair of strips, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said body first end portion, whereby said pairs of right angled and obtuse angled terminal feet at said first end portion of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles and said pairs of terminal feet at said second end portion of said body are at different angles to thus permit access to the terminal screws by a tool in different angular positions without short circuiting any two of the terminal screws.

9. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs aligned and closely spaced, said screw terminal comprising, first and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, a central finger extending from said first portion of said body, first and second sloping shoulders on said first end portion lying on either side of said central finger and longitudinally displaced from the end thereof, a second finger extending from said second end portion of said body, a recess surface longitudinally spaced from the end of said second finger, each body half having surfaces defining slots extending from said first to said second end portion, means for fastening together said body halves in complementary relationship, first, second, third, and fourth conductor strips disposed in said slots in said body halves with said first and fourth strips being a first pair and at least partially contained in said second finger and said second and third strips being a second pair and at least partially contained in said central finger, a right angled terminal foot on each of said second pair of strips disposed in a reference plane and adjacent the end of said central finger, an obtuse angled terminal foot on each of said first pair of strips adjacent said sloping shoulders, a second right angled terminal foot on each of one pair of strips at said second end portion, a second obtuse angled terminal foot on each of the other pair of strips at said second end portion, one pair of strips having at least one terminal foot thereof at said second end portion disposed adjacent the end of said second finger, the other pair of strips having the terminal feet thereof at said second end portion disposed adjacent said recess surface, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said first end portion, whereby said pairs of right angled and obtuse angled terminal feet at said first and second end portions of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles to thus permit access to the terminal screws by a tool in different angular positions without short circuiting any two of the terminal screws.

10. A screw terminal for an electrical device having four spade lugs as terminals thereon with two of the spade lugs aligned and closely spaced, said screw terminal comprising, first and second insulated body halves complementarily engageable to form a body, said body having a first and a second end portion with a mounting flange therebetween to mount to a mounting panel, a central finger extending from said first end portion of said body, first and second sloping shoulders on said first end portion lying on either side of said central finger and longitudinally displaced from the end thereof, first and second spaced fingers extending from said second end portion of said body, a recess disposed between and longitudinally spaced from the ends of said first and second extending spaced fingers, each body half having surfaces defining slots extending from said first to said second end portion, means for fastening together said body halves in complementary relationship, first, second, third, and fourth conductor strips all of substantially equal length and disposed in said slots in said body halves with said first and fourth strips being a first pair and contained in said spaced fingers and said second and third strips being a second pair and contained in said central finger, a right angled terminal foot on each of said second pair of strips disposed in a reference plane and adjacent the end of said central finger, an obtuse angled terminal foot on each of said first pair of strips adjacent said sloping shoulders, a second right angled terminal foot on each of one pair of strips at said second end portion, a second abtuse angled terminal foot on each of the other pair of strips at said second end portion, said first pair of strips having the terminal feet thereof at said second end portion disposed adjacent the ends of said first and second extending spaced fingers, said second pair of strips having the terminal feet thereof at said second end portion disposed adjacent the surface of said recess, a threaded aperture in each of said feet, a terminal screw threaded into each threaded aperture to receive the spade lugs at said first end portion, whereby said pairs of right angled and obtuse angled terminal feet at said first and second end portions of said body are differently spaced relative to said reference plane and have the terminal screws for the pairs of feet disposed at acute angles to thus permit access to the terminal screws by a tool in difierent angular positions without short circuiting any two of the terminal screws.

References Cited in the file of this patent UNITED STATES PATENTS 1,654,143 Russell Dec. 27, 1927 2,318,230 Jones May 4, 1943 2,336,599 MacInnis Dec. 14, 1943 2,457,535 Diethert Dec. 28, 1948 2,465,540 Korn Mar. 29, 1949 2,636,065 Fiske Apr. 21, 1953 FOREIGN PATENTS 509,061 Germany Oct. 3, 1930 676,870 Germany June 14, 1939 

